Before saying farewell to a discussion of the “Language and Life History” article by John Locke and Barry Bogin (abstract here) I want to present in full their unusual account of how speech (what they call vocal-verbal behavior) evolved.
They begin by quoting Jerry A. Hogan,
[natural selection] should operate at all stages of development and not only on the adult outcome, since any developmental process that reduces the probability of reaching adulthood will be very strongly selected against. (p 265)
We have seen on this blog that Locke and Bogin emphasize the insertion of childhood and adolescent stages into the human life cycle, so the quotation is not quite on point. It focuses on negative selection (rejecting changes), while we would look for evidence of positive selection (adding changes). The insertion of two unprecedented life stages can hardly be explained by genetic drift. The quotation’s general point, however, that all life stages play important parts in evolution is important and it provides justification, if any were required, for the article’s unusual approach of looking at changes in human life cycles and their implications for the origins of speech.
They propose an unusual selection mechanism, parental selection. Normally, parents do what they can with what they’ve got although sometimes they ignore the runt of the litter. But in cases where mothers give birth to only one live infant at a time they have little choice. Humans infants, however, are unusually dependent for a long time, leaving them subject to the dangers of negligence and abusive anger. To lessen these risks, it is in the infants’ interest to strengthen the bond between infant and parent.
This strengthening is accomplished by children’s soft vocalizations, babbling coocoo, mama, bobo, etc. With these sounds they catch and hold a parent’s attention without making demands of the sort that crying imposes. This process resulted in the evolution of a species with greater vocal flexibility than is found in other primates.
These soft vocalizations can “trickle-up” from infant to parent. Although we usually think of infants imitating their care-takers, it often works the other way around as well, with the mother imitating the baby. “One reason they do this may be to control their infant’s attention. … [One study found] that infants ‘pay special attention … when the mothers themselves imitate an action which the child has just performed.’” (p. 266) Thus these baby sounds can trickle-up to the parents and become regular features of vocabulary; it is the baby who is the instrument of evolutionary change.
Modern human infants and children have “instincts for [linguistic] inventiveness,” meaning they will create a language if they are not surrounded by one. The same instinct may have existed when speech was originating, but the authors acknowledge that this modern trait may itself be a product of linguistic evolution and they do not push this idea very heavily. Nothing in their scenario seems to depend on it.
The vocal flexibility developed in infancy could have been used by kin groups to exchange information, enabling the young to learn what the elders already knew, and providing a survival advantage to those kin groups that did so. But, say the authors, this interaction between kin is too restricted to be the whole story.
This section in Locke/Bogin seems especially clumsy. Many of their peers complained that this section offers no explanation for why the same sort of advantage wouldn’t fall to kin groups of other primate species as well, but those objections reflect a misreading. It is the peculiarities of bipedal dependency that lead to the development of vocal flexibility and a small set of shared words, providing the basic physical ability to create the variable sounds that support speech.
The clumsiness I note is that it is very hard to get from a few words to sharing information, and there is an infinite amount of information, even in a primate family, that might be shared. Locke/Bogin refer to the way babbling and imitative babbling uses sound to manipulate attention, but do not then join the revolution preached on this blog that the task of meaningful speech is to direct the listener’s attention. This thesis suggests something the kin group could have been doing with its limited speech. It was showing (not just telling) the young how to survive. It taught them where attention could be most profitably be directed.
Play between children beyond the kin group may have been important in spreading speech and enlarging it. This idea is exactly what Judy Kegl and her team reported from observing the creation of a sign language among deaf children in Nicaragua. Children arrived at the school for the deaf with a few signs they had developed at home, but once they came together they turned those individual home signs into a common language. I am at a loss to understand why Locke/Bogin do not mention this work. (The article and commentary’s bibliography runs over a dozen pages.) Even more peculiar is the fact that the only people who do mention the work are Sonia Ragir and Patricia Brooks, authors of a very hostile review of Locke/Bogin (abstract here).
Studies of emergent Sign Languages and Creoles indicate greater complexity and systematicity in the negotiated exchange of information within and between groups composed of relative strangers as opposed to close kin. (p. 296)
Their complaint is true, but supports Locke/Bogin’s idea of spread through play if only they had cared to point it out.
When adolescents interact they “not only manipulate language in new ways, but also revise it…. Nonstandard forms tend to originate preferentially with males, doing so at some point between late juvenility and early adolescence.” (p. 267) Ignoring the nonsense about males (have they never heard of Valley Girls and, like, their speech improvisations?), it seems true that adolescents are creative, influential speakers. We need only note that teenagers seem to be a bottomless well of new slang, but Locke/Bogin stop here, most anticlimactically. (See yesterday’s post for my meditation on how the initiation of adolescents into adult society might be responsible for a new, ceremonial, type of communication.)
May I pick three elements from your summary of proposals by Locke and Bogin? They are:
The infant sounds coocoo, mama and bobo
The imitations, of infant by mother and of mother by infant
The instinct for inventiveness.
If we agree that humans get pleasure, an internal reward, when two things match, this clearly underlies the first two, but what about the third?
Inventiveness in language is not a primal instinct, it derives from having something to say. Ideas in the mind come first; it is a mind rich in ideas that invents language. (For sure, once invented, language facilitates later ideas, but at Babel’s dawn ideas were the driver.) Further, inventiveness derives from having something to say for which grunts and gestures do not suffice; it derives from possessing ideas that go beyond the here-and-now --- in short, abstract ideas. And here’s the point: an internal reward from noting items that match promotes forming abstract ideas endlessly, just for the fun. If we seek a reason for the endless inventiveness in human language, the internal reward from putting like with like fills the bill.
William James 1892: “… (animals) never extract characters for the mere fun of the thing, as men do.”
Psychology, p.369; New York, Henry Holt and Co.
Of course, women do too. To “extract a character” is his term for forming an abstract concept from a group of instances. The idea that chimpanzee infants get a little fun from such activity, but significantly less fun than human infants, appears in experiments by Langer, Spinozzi and associates: Human Evolution 13 (1998), 107-124 and 125-139. (I am not aware of these experiments having been replicated or extended, but may have missed more recent work.)
Posted by: Brian Bayly | February 04, 2007 at 01:43 PM